无锁定的退化的等参壳元

构造了一个无锁定的8节点退化的等参壳元。在自然坐标系中,对横向剪应变项插值修正使单元满足必要的模式(平移、转动和纯弯曲)以消除"剪切锁定";在局部坐标系中,对薄膜应变插值修正以消除"薄膜锁定"。这样构造的8节点单元的刚度矩阵具有正确的秩,同时具有恰当的零特征值和相应的刚体位移模式。这种单元对大跨-厚比情形既无"剪切锁定"又无"薄膜锁定",无虚假的零能模式和机构出现,可用于厚壳和薄壳。

Locking-Free DegeneratedIsoparametric Shell Element

An 8_noded locking_free degenerated isoparametric shell element is presented. A revised interpolation for shear strain terms was constructed in natural co_ordinate system such that all necessary modes (translation, rotation and constant curvature) are preserved, which can be used to eliminate shear locking. A revised interpolation for membrane strains was produced in the local Cartesian co_ordinate system to overcome membrane locking behavior. The new 8_noded element has the proper rank, with the requisite number of zero eigenvalues each associated with a rigid mode. The element does not exhibit membrane or shear locking for large span_thickness ratio. The element does not form element mechanisms or extra spurious zero energy modes. Therefore, it can be used for both thin and thick shells.